Boric Acid\nCross-Linking Strategy for Enhancing Room\nTemperature Phosphorescence of Poly(Vinyl Alcohol)-Doped Films

Organic room temperature phosphorescence\n(RTP) has attracted\nincreasing\nattention owing to its unique luminous properties and wide applications.\nHowever, the trade-off between the phosphorescence quantum yield (Φ<sub>Phos</sub>) and the phosphorescence lifetime (τ<sub>Phos</sub>) highlights the necessity for developing new strategies to enhance\nRTP performance. While research often focuses on guest components\nin polymer-based host–guest RTP systems, the host materials,\nwhich provide rigid environments, are less explored. This work introduces\na simple and efficient strategy to develop RTP materials with high\nefficiency and long lifetime by employing covalent cross-linking to\nmodify the rigidity of the polymer matrix. By suppressing nonradiative\ndecay and decreasing luminescence quenching under ambient conditions,\nnot only the Φ<sub>Phos</sub> of cross-linked films is improved\nfrom 3.2% to 13.5%, but also the τ<sub>Phos</sub> is extended\nfrom 482.34 to 625.23 ms. Thanks to its solution processability and\nwater sensitivity, this RTP system was successfully applied in inkjet\nprinting and binary anticounterfeiting.